One of my first rules of robocars is “you don’t change the infrastructure.” Changing infrastructure is very hard, very expensive, requires buy-in from all sorts of parties who are slow to make decisions, and even if you do change it, you then have a functionality that only works in the places you have managed to change it. New infrastructure takes many decades — even centuries, to become truly ubiquitous.
That’s why robocar enthusiasts have been skeptical of things like ITS plans for roadside to vehicle and vehicle to vehicle communications, plans for dedicated highway lanes with special markers, and for PRT which needs newly built guideways. You have to work with what you have.
There are some ways to bend this rule. Some infrastructure changes are not too hard — they might just require something as simple and cheap as repainting. Some new infrastructures might be optional — they make things better in the places you put them, but they are not necessary to operations. Some might focus on specific problem areas — like special infrastructure in heavy pedestrian areas or parking lots, enabling or improving optional forms of operation in those areas.
Another possiblility is to have robocars enable a form of new infrastucture, turning it upside down. The infrastructure might need the robocars rather than the other way around. I wrote about that sort of plan when discussing a solar panel on a robocar.
A recent proposal from Siemens calls for having overhead electric wires for trucks. Trolley buses and trams use overhead electric wires, and there are hybrid trolley buses (like the Boston T line) which can run either on the wires or on an internal diesel. These trucks are of that type. The main plan for this is to put overhead wires in things like shipping ports, where trucks are running around all the time, and they would benefit greatly from this.
I’ve seen many proposals for electrication of the roads. Overhead wires are problematic because they need to be high enough to go over the trucks and other high vehicles, but that makes them harder to reach by low vehicles. You need two wires and must get good contact. They are also damn ugly. This has lead to proposals for inductive power supplies buried in the road. This is very expensive as it requires tearing up the road. There are also inductive losses, and while you don’t need to make contact, precise driving is important for efficiency. In these schemes, battery-electric cars would be able to avoid using their batteries (and in fact charge them) while on the highway, vastly increasing their range and utility.
Robocars offer highly precise driving. This would make it easier to line up on overhead wires or inductive coils in the road. It even would make it possible to connect with rails in the roadbed, though right now people don’t want to consider having a high voltage rail on the ground, even on a highway.
It was proposed to me (I’m trying to remember by who — my apologies) that one new option would be a rail on the side of the highway. This lane would be right up against the guardrail, and normally would be the shoulder. In the guardrail would be power rails, and a connector would come from the left side of the vehicle. Only a robot would be able to drive so precisely as to do this safely. Even with a long pole and more distance I am not sure people would enjoy trying to drive like this. A grounding rail in the roadbed might also be an option — though again tearing up the roadbed is very expensive to do and maintain.
There is still the problem of having a live rail or wire at reachable height. The system might be built with an enclosed master cable and then segments of live wire which are only live when a vehicle is passing by them. Obviously a person doesn’t want to be there when a car is zooming through. This requires roboust switching eqiupment for the thousands of watts one wishes to transfer. You also have to face the potential that a car from the regular lanes could crash into the rail and wires, and while that’s never going to be safe you don’t want to make it worse. You also need switching if you are going to have accounting, so only those who pay for it get power. (Alternately it could be sold by a subscription so you don’t account for the usage and you identify cars that don’t have a subscriber tag who are sucking juice and fine them.)
There is also the problem that this removes the shoulder which provides safety to other cars and provides a breakdown lane. If a vehicle does have to stop in this lane for emergency reasons, sensors in the rail could make sure that all robocars would know and leave the lane with plenty of margin. They would all have batteries or engines and be able to operate off the power — indeed the power lines need not be continuous, you don’t have to build them in sections of the road where it’s difficult. If other cars are allowed to enter the lane, it must not be dangerous other than physically for them to brush the wires.
It’s also possible that the rail could be inductive. The robocar could drive and keep its inductor contact just a short distance from the coils in the rail. This is more expensive than direct contact, and not as efficient, but it’s a lot cheaper than burying inductors in the roadbed. It’s safe for pedestrians and most impacts, and while a hard impact could expose conductors, a ground fault circuit could interrupt the power. Indeed, because all vehicles on the line will have alternate power, interruption in the event of any current not returning along the return is a reasonable strategy.
For commuters with electric cars, there is a big win. You can get by with far less battery and still go electric. The battery costs a lot of money — more than enough to justify the cost of installing the connection equipment. And having less battery means less weight, and that’s the big win for everybody, as you make the vehicles more efficient when you cut out that weight. Of course, if this lane is only for use by electrified robocars, it becomes a big incentive to get one just to use the special lane.
The power requirements are not small. Cars will want 20kw to go at highway speed, and trucks a lot more. This makes it hard to offer charging as well as operating current, but smaller cars might be able to get a decent charge while driving.